Fraction of the X-ray selected AGNs with optical emission lines in
... 2009). For a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS spectroscopic redshift survey, Silverman et al. (2009) identified 147 AGNs, and found no significant difference of AGN fraction in groups with that in fields. Compared with optically selected AGNs, the AGNs revealed by ...
... 2009). For a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS spectroscopic redshift survey, Silverman et al. (2009) identified 147 AGNs, and found no significant difference of AGN fraction in groups with that in fields. Compared with optically selected AGNs, the AGNs revealed by ...
The Emission Line Spectrum of Active Galactic
... 2.1.2. The emission line spectrum of Seyfert 1 galaxies and QSOs In addition to a narrow-line emission spectrum, Seyfert 1s have broad permitted lines (H I, He I λλ5876,6678,7065, He II λ4686 and Fe II in the visible domain). The narrow-line spectra of Seyfert 1s are very similar to those of Seyfert ...
... 2.1.2. The emission line spectrum of Seyfert 1 galaxies and QSOs In addition to a narrow-line emission spectrum, Seyfert 1s have broad permitted lines (H I, He I λλ5876,6678,7065, He II λ4686 and Fe II in the visible domain). The narrow-line spectra of Seyfert 1s are very similar to those of Seyfert ...
Power Point Presentation
... upper atmosphere, report Stanford researchers. It is the first time that a significant change in Earth's environment has been traced to energy from a distant star. (from the NASA press release) ...
... upper atmosphere, report Stanford researchers. It is the first time that a significant change in Earth's environment has been traced to energy from a distant star. (from the NASA press release) ...
Infrared identification of high-mass X
... compact objects associated with a supergiant donor that undergo fast and transient outbursts in the X-ray domain of the electromagnetic spectrum. These latter sources are called supergiant fast X-ray transients (SFXT; Negueruela et al. 2006), which represented by their archetype, IGR J17544-2619 (Pe ...
... compact objects associated with a supergiant donor that undergo fast and transient outbursts in the X-ray domain of the electromagnetic spectrum. These latter sources are called supergiant fast X-ray transients (SFXT; Negueruela et al. 2006), which represented by their archetype, IGR J17544-2619 (Pe ...
Observation of the Crab pulsar wind nebula and microquasar Ph.D. Dissertation
... and Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes, have been capable to increase the total number of known VHE emitting sources from a few to almost one hundred in just seven years of operation. This population comprises galactic and extragalactic objects. IACTs have proved to be ...
... and Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes, have been capable to increase the total number of known VHE emitting sources from a few to almost one hundred in just seven years of operation. This population comprises galactic and extragalactic objects. IACTs have proved to be ...
MAXI J1659-152 - UvA-DARE
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
MAXI J1659-152: The shortest orbital period black
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
Double relics in Abell 2345 and Abell 1240
... the Coma cluster relic, and only recently a temperature gradient has been found near the relic in Abell 548b by Solovyeva et al. (2008). Here, a precise orientation of the cluster merger with respect to the line of sight is inferred, and the projected displacement of the relic from the shock is thus ...
... the Coma cluster relic, and only recently a temperature gradient has been found near the relic in Abell 548b by Solovyeva et al. (2008). Here, a precise orientation of the cluster merger with respect to the line of sight is inferred, and the projected displacement of the relic from the shock is thus ...
MAXI J1659−152: the shortest orbital period black
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
... weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414 ± 0.005 h, whic ...
GRB prompt emission
... – compare with equipartition Most energy estimates require knowledge of the geometry of the outflow – radius and cross check with ISS-derived radius ...
... – compare with equipartition Most energy estimates require knowledge of the geometry of the outflow – radius and cross check with ISS-derived radius ...
GRB prompt emission
... – compare with equipartition Most energy estimates require knowledge of the geometry of the outflow – radius and cross check with ISS-derived radius ...
... – compare with equipartition Most energy estimates require knowledge of the geometry of the outflow – radius and cross check with ISS-derived radius ...
Gamma Ray Bursts
... Compactness problem Short burst duration (0.01-100s) suggests compact source (~1000 km) – light must go through the source High luminosity and large distance imply high energy released. Compact source implies high energy density photons interact and produce e+e- pairs spectrum should not contai ...
... Compactness problem Short burst duration (0.01-100s) suggests compact source (~1000 km) – light must go through the source High luminosity and large distance imply high energy released. Compact source implies high energy density photons interact and produce e+e- pairs spectrum should not contai ...
AVS03ML - Brigham Young University
... (A quote from the Center for X-ray Optics) The primary interaction of low-energy x rays within matter, viz. photoabsorption and coherent scattering, have been described for photon energies outside the absorption threshold regions by using atomic scattering factors, f1 and f2. The atomic photoabsorpt ...
... (A quote from the Center for X-ray Optics) The primary interaction of low-energy x rays within matter, viz. photoabsorption and coherent scattering, have been described for photon energies outside the absorption threshold regions by using atomic scattering factors, f1 and f2. The atomic photoabsorpt ...
The impact of surface temperature inhomogeneities on quiescent
... magnetized (B ≪ 109 G), therefore the effects of the magnetic field on the opacity and equation of state of the atmosphere can be neglected. The opacity within the atmosphere is due to a combination of thermal free-free absorption and Thomson scattering. Light-element neutron star atmosphere models ...
... magnetized (B ≪ 109 G), therefore the effects of the magnetic field on the opacity and equation of state of the atmosphere can be neglected. The opacity within the atmosphere is due to a combination of thermal free-free absorption and Thomson scattering. Light-element neutron star atmosphere models ...
The effect of helium sedimentation on galaxy cluster masses and
... Sunyaev-Zel’dovich effect (SZE) may be used to infer the helium abundance in the ICM (Markevitch 2007); however, the limited resolution and sensitivity of current SZE interferometers have so far not enabled the measurement of the distribution of helium, even in the cluster cores where the sedimentati ...
... Sunyaev-Zel’dovich effect (SZE) may be used to infer the helium abundance in the ICM (Markevitch 2007); however, the limited resolution and sensitivity of current SZE interferometers have so far not enabled the measurement of the distribution of helium, even in the cluster cores where the sedimentati ...
JENAM-2011 Book of abstracts
... probability for a massive star to become an accretion powered X-ray source once upon its lifetime. This explains the unexpectedly high contribution of accreting compact objects of stellar mass to the Cosmic X-ray background, ∼7-10%. Underneath bright X-ray binaries, unresolved emission is present in ...
... probability for a massive star to become an accretion powered X-ray source once upon its lifetime. This explains the unexpectedly high contribution of accreting compact objects of stellar mass to the Cosmic X-ray background, ∼7-10%. Underneath bright X-ray binaries, unresolved emission is present in ...
Astronomy Astrophysics
... (ISO) spectrophotometric measurements in the 2.4–12 µm range was to constrain further the nature of the companion star to the compact object: the expected strong He lines as well as the metallic lines in different ionization states are important clues, together with the spectral shape of the continu ...
... (ISO) spectrophotometric measurements in the 2.4–12 µm range was to constrain further the nature of the companion star to the compact object: the expected strong He lines as well as the metallic lines in different ionization states are important clues, together with the spectral shape of the continu ...
chapter 5—x-ray equipment
... a. overhead tube suspension system c. floor tube suspension system b. floor-to-ceiling tube suspension system d. mobile tube suspension system ANS: A ...
... a. overhead tube suspension system c. floor tube suspension system b. floor-to-ceiling tube suspension system d. mobile tube suspension system ANS: A ...
Composition-Tunable Properties Of CdSxTe1
... in the first group have a pronounced nonlinear dependence on the ratio of two chalcogens in the alloy and thus could be difficult to predict. For instance, it was found2 that emission energies of CdSexTe1-x NCs are well outside the range of transition energies of contributing CdSe and CdTe binary QD ...
... in the first group have a pronounced nonlinear dependence on the ratio of two chalcogens in the alloy and thus could be difficult to predict. For instance, it was found2 that emission energies of CdSexTe1-x NCs are well outside the range of transition energies of contributing CdSe and CdTe binary QD ...
X-ray spectra of highly magnetized neutron stars in binary systems
... CRSF in the spectrum. While one line at ∼50 keV has been observed by many instruments, a second line at ∼24 keV had been reported by Kretschmar et al. (1996), while other observers (Orlandini et al. 1997) could not detect this line. Using pulse phase resolved spectroscopy (in pulse phase resolved sp ...
... CRSF in the spectrum. While one line at ∼50 keV has been observed by many instruments, a second line at ∼24 keV had been reported by Kretschmar et al. (1996), while other observers (Orlandini et al. 1997) could not detect this line. Using pulse phase resolved spectroscopy (in pulse phase resolved sp ...
PowerPoint file - Departament d`Astronomia i Meteorologia
... (the systemic velocity is 11.2 km s-1). The integrated emission for the low-velocities, from 8 to 14 km s-1 reveals two filamentary structures associated with the fan-shape structure found in H2. From the low-velocity map, it is also clear the association of CO(2-1) with IRS 1, as well as the presen ...
... (the systemic velocity is 11.2 km s-1). The integrated emission for the low-velocities, from 8 to 14 km s-1 reveals two filamentary structures associated with the fan-shape structure found in H2. From the low-velocity map, it is also clear the association of CO(2-1) with IRS 1, as well as the presen ...
Analysis of Stellar Activity and Orbital Dynamics in Extrasolar
... The area of exoplanet research, which emerged less than two decades ago, was revolutionized with the advent of space-based photometers like CoRoT and Kepler. These observatories provide long-term monitoring of thousands of stars with unprecendented accuracy and high time resolution to detect transit ...
... The area of exoplanet research, which emerged less than two decades ago, was revolutionized with the advent of space-based photometers like CoRoT and Kepler. These observatories provide long-term monitoring of thousands of stars with unprecendented accuracy and high time resolution to detect transit ...
Core-Halo Age Gradients and Star Formation in the Orion Nebula
... While considerable insights have been gained regarding the formation of stars on small scales, the formation of rich stellar clusters dominated by OB stars is quite uncertain. Debate has waged for decades over the relative importance of rapid ‘top-down’ fragmentation or a slower ‘bottom-up’ process ...
... While considerable insights have been gained regarding the formation of stars on small scales, the formation of rich stellar clusters dominated by OB stars is quite uncertain. Debate has waged for decades over the relative importance of rapid ‘top-down’ fragmentation or a slower ‘bottom-up’ process ...
potenza dei jet nei nuclei galattici attivi radio
... radiation fields responsible for photoionizing the galactic nebulae where they came from. AGNs are thought to host at their centers a massive compact object with mass M ∼ 106 –109 M , where M = 1.9891 · 1033 g corresponds to the unit solar mass. Another feature of an AGN’s optical-UV (Ultra Violet ...
... radiation fields responsible for photoionizing the galactic nebulae where they came from. AGNs are thought to host at their centers a massive compact object with mass M ∼ 106 –109 M , where M = 1.9891 · 1033 g corresponds to the unit solar mass. Another feature of an AGN’s optical-UV (Ultra Violet ...
Systematic variation in the apparent burning area of thermonuclear
... of Astronomy and Maryland Astronomy Center for Theory and Computation, University of Maryland, College Park, MD 20742-2421, USA 3 Center for Stellar and Planetary Astrophysics, Monash University, Victoria 3800, Australia 2 Department ...
... of Astronomy and Maryland Astronomy Center for Theory and Computation, University of Maryland, College Park, MD 20742-2421, USA 3 Center for Stellar and Planetary Astrophysics, Monash University, Victoria 3800, Australia 2 Department ...
X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy is the space science related to a type of space telescope that can see farther than standard light-absorption telescopes, such as the Mauna Kea Observatories, via x-ray radiation.X-ray emission is expected from astronomical objects that contain extremely hot gasses at temperatures from about a million kelvin (K) to hundreds of millions of kelvin (MK). Although X-rays have been observed emanating from the Sun since the 1940s, the discovery in 1962 of the first cosmic X-ray source was a surprise. This source is called Scorpius X-1 (Sco X-1), the first X-ray source found in the constellation Scorpius. The X-ray emission of Scorpius X-1 is 10,000 times greater than its visual emission, whereas that of the Sun is about a million times less. In addition, the energy output in X-rays is 100,000 times greater than the total emission of the Sun in all wavelengths. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002. It is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects.Many thousands of X-ray sources are known. In addition, the space between galaxies in galaxy clusters is filled with a very hot, but very dilute gas at a temperature between 10 and 100 megakelvins (MK). The total amount of hot gas is five to ten times the total mass in the visible galaxies.